随笔分类 -  LeetCode Solutions

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Solutions to problems on https://leetcode.com/problemset/algorithms/.
[LeetCode] Sum of Two Integers
摘要：The code is as follows. The above code may be rewritten to make it more readable. c stands for the carry bit of adding two integers. The sum of two in 阅读全文
posted @ 2016-09-10 21:47 jianchao-li 阅读(372) 评论(0) 推荐(0)
[LeetCode] Ransom Note
摘要：A very typical application of hash maps. Since I am now learning Java, I code in Java. The following code uses toCharArray() and getOrDefault(), which 阅读全文
posted @ 2016-08-14 21:57 jianchao-li 阅读(524) 评论(0) 推荐(0)
[LeetCode] Sparse Matrix Multiplication
摘要：Problem Description:Given twosparse matricesAandB, return the result ofAB.You may assume thatA's column number is equal toB's row number.Example:A = [... 阅读全文
posted @ 2015-12-03 13:39 jianchao-li 阅读(4581) 评论(0) 推荐(0)
[LeetCode] Range Sum Query - Mutable
摘要：This problem requires a new data structure --- Segment Tree. You may use this GeeksforGeeks article to get some ideas of it. However, the code in this... 阅读全文
posted @ 2015-11-23 17:14 jianchao-li 阅读(1508) 评论(0) 推荐(0)
[LeetCode] Additive Number
摘要：Af first I read the title as "Addictive Number". Anyway, this problem can be solved elegantly using recursion. This post shares a nice recursive C++ c... 阅读全文
posted @ 2015-11-20 13:16 jianchao-li 阅读(871) 评论(0) 推荐(0)
[LeetCode] Number of Islands II
摘要：Problem Description:A 2d grid map ofmrows andncolumns is initially filled with water. We may perform anaddLandoperation which turns the water at posit... 阅读全文
posted @ 2015-11-14 20:55 jianchao-li 阅读(7312) 评论(0) 推荐(0)
[LeetCode] Range Sum Query 2D - Immutable
摘要：Very similar to Range Sum Query - Immutable, but we now need to compute a 2d accunulated-sum. In fact, if you work in computer vision, you may know a ... 阅读全文
posted @ 2015-11-12 22:00 jianchao-li 阅读(673) 评论(0) 推荐(0)
[LeetCode] Range Sum Query - Immutable
摘要：The idea is fairly straightforward: create an arrayaccuthat stores the accumulated sum fornumssuch thataccu[i] = nums[0] + ... + nums[i]in the initial... 阅读全文
posted @ 2015-11-10 13:43 jianchao-li 阅读(993) 评论(0) 推荐(0)
[LeetCode] Smallest Rectangle Enclosing Black Pixels
摘要：This post shares very detailed explanation of how to use binary search to find the boundaries of the smallest rectangle that encloses the black pixels... 阅读全文
posted @ 2015-11-08 21:00 jianchao-li 阅读(1285) 评论(0) 推荐(0)
[LeetCode] Remove Invalid Parentheses
摘要：This problem can be solved very elegantly using BFS, as in this post.The code is rewritten below in C++. 1 class Solution { 2 public: 3 vector rem... 阅读全文
posted @ 2015-11-05 15:38 jianchao-li 阅读(1438) 评论(0) 推荐(0)
[LeetCode] Longest Increasing Subsequence
摘要：A typical O(n^2) solution uses dynamic programming. Let's use lens[j] to denote the length of the LIS ending with nums[j]. The state equations arelens... 阅读全文
posted @ 2015-11-03 22:15 jianchao-li 阅读(412) 评论(1) 推荐(0)
[LeetCode] Bulls and Cows
摘要：This problem seems to be easy at the first glance, especially the problem gives a too much simpler example. Make sure you understand the problem by ma... 阅读全文
posted @ 2015-10-31 18:23 jianchao-li 阅读(354) 评论(0) 推荐(0)
[LeetCode] Binary Tree Longest Consecutive Sequence
摘要：Problem Description:Given a binary tree, find the length of the longest consecutive sequence path.The path refers to any sequence of nodes from some s... 阅读全文
posted @ 2015-10-30 16:55 jianchao-li 阅读(2287) 评论(0) 推荐(0)
[LeetCode] Serialize and Deserialize Binary Tree
摘要：I adopt a way similar to that of the OJ to serialize the binary tree. For the following tree, my serialization result is "1,2,3,null,null,4,5," (note ... 阅读全文
posted @ 2015-10-30 15:51 jianchao-li 阅读(850) 评论(0) 推荐(0)
[LeetCode] Best Meeting Point
摘要：Problem Description:A group of two or more people wants to meet and minimize the total travel distance. You are given a 2D grid of values 0 or 1, wher... 阅读全文
posted @ 2015-10-22 16:34 jianchao-li 阅读(3899) 评论(0) 推荐(1)
[LeetCode] Find Median from Data Stream
摘要：This post shares a very nice solution using two heaps: a max heap for the smaller half and a min heap for the larger half. The code is rewritten below... 阅读全文
posted @ 2015-10-19 23:53 jianchao-li 阅读(1613) 评论(0) 推荐(0)
[LeetCode] Flip Game II
摘要：Problem Description:You are playing the following Flip Game with your friend: Given a string that contains only these two characters:+and-, you and yo... 阅读全文
posted @ 2015-10-17 00:20 jianchao-li 阅读(6546) 评论(0) 推荐(0)
[LeetCode] Flip Game
摘要：Problem Description:You are playing the following Flip Game with your friend: Given a string that contains only these two characters:+and-, you and yo... 阅读全文
posted @ 2015-10-15 13:54 jianchao-li 阅读(6213) 评论(0) 推荐(0)
[LeetCode] Nim Game
摘要：Haha, an interesting problem. Just try to let your opponent start with a number that is an integer multiple of 4.1 class Solution {2 public:3 bool... 阅读全文
posted @ 2015-10-13 16:41 jianchao-li 阅读(215) 评论(0) 推荐(0)
[LeetCode] Word Pattern II
摘要：Problem Description:Given apatternand a stringstr, find ifstrfollows the same pattern.Herefollowmeans a full match, such that there is a bijection bet... 阅读全文
posted @ 2015-10-12 00:08 jianchao-li 阅读(5014) 评论(0) 推荐(0)

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